1. Field of the Invention
The present invention relates to an autonomous moving apparatus arranged to autonomously move. In particular, the present invention relates to an autonomous moving apparatus arranged to estimate a self-position and/or generate a global map of the surroundings of the autonomous moving apparatus while moving.
2. Description of the Related Art
A conventionally-known autonomous moving apparatus (for example, a robot or an unmanned transfer vehicle) moves autonomously in an environment such as a hospital, office, warehouse, factory, or the like. In order for the autonomous moving apparatus to autonomously move in the environment, it needs a global map of the surroundings (hereinafter, referred to as the “global map”) of a set position of the autonomous moving apparatus and position (self-position) information of the autonomous moving apparatus on the global map. A Simultaneous Localization and Mapping (SLAM) technique, which simultaneously estimates a self-position and generates a global map in real time, has been attracting attention in the technical field of the autonomous moving apparatus. In the SLAM technique, the autonomous moving apparatus includes a distance measuring sensor such as, but not limited to, a Laser Range Finder (LRF), for example, acquires a local map of the surroundings (hereinafter, referred to as the “local map”) of the apparatus by measuring a distance between the apparatus and an object (for example, walls and obstacles, etc.) that exists in the surroundings of the apparatus with the sensor, estimating the self-position based on the local map, and generating or updating the global map.
The above laser range finder emits a laser, detects when the laser is reflected by an object, measures time from when the laser is emitted until when a reflected wave is detected, and thus measures the distance between the autonomous moving apparatus and the object. Further, the laser range finder includes a rotating mirror, reflects the emitted laser by the rotating mirror, scans the laser in a fan-shaped form in a horizontal direction, for example, and thus detects the shape of objects that exist in the surroundings of the autonomous moving apparatus. When the autonomous moving apparatus accelerates/decelerates, for example, or when the autonomous moving apparatus has made (or is in) contact with an obstacle, the autonomous moving apparatus inclines, and the laser range finder of the autonomous moving apparatus resultantly inclines. When the laser range finder inclines, an output direction of the laser varies. As a result, a position or an object that is different from the position or the object that is supposed to be irradiated with the laser when the laser range finder is not inclined is irradiated with the laser, and consequently, a distance (incorrect distance) between the apparatus and the position or the object that is different from the position or object detected in a normal state (i.e., the state in which the laser range finder is not inclined) may be detected. When the apparatus detects the distance between the apparatus and the position or the object that is different from the position or the object that is supposed to be detected, the self-position is improperly estimated based on the incorrect detected distance, and the incorrect self-position may be estimated. Moreover, when the global map is generated or updated based on the incorrect detected distance, an incorrect global map may be generated or updated.